However, the percentage increase of lignin content in pre- treated fibers are lower than that of holocellulose and alpha-cellulose due to the fact that cellulose is insoluble and more durable than other components.
In addition, cellulose is an important factor for heat insulation and sound absorption proper- ties of fiber cement materials Morphological and structural changes of the fibers were investigated using scanning electron microscopy(SEM), SEM is an important tool for observing the surface morphology of 2 shows SEM micro- unpretreated and pretreated fiber graphs of coconut coir fiber and oil palm fiber before and after pretreatment.
The surface morphology of unpretreated fibers were different to those of pretreated fibers in terms of rough ness, smoothness and cavity. The surfaces of the unpretreated fibers were not smooth, spread with nodes and irregular stripes, which is covered with substances and other impurities. A com parison between coconut coir fiber and oil palm fiber showed that coconut coir fiber has a smoother and more uniform surface due to the lower amount of impurities such as as content Pretrea ment removal of low molecular pounds.
resulting in a formation of slightly rough surface and I.
Consequently, the washed increasing amount of voids l and boiled fiber has an increment of surface area, lower density and greater moisture absorption